Toggle lever operating arrangement for a press



March 20, 1956 Filed Jan. 29, 1952 6 Sheets-Sheet l VIII/[IA V INVENTOR:HELmvT H March 20, 1956 H. HE HT 2,738,748

TOGGLE LEVER OPERATING ARRANGEMENT FOR A PRESS Filed Jan. 29, 1952 6Sheets-Sheet 5 INVENTOR. HELrm/ HECHT March 20, 1956 HECHT 2,738,748

TOGGLE LEVER OPERATING ARRANGEMENT FOR A PRESS Filed Jan. 29. 1952 '6SheetsSheet 5 IHVEN'TDR: H ELMUT' HEWT March 20, 1956 H. HECHT 2,738,748

TOGGLE LEVER OPERATING ARRANGEMENT FOR A PRESS Filed Jan. 29, 1952 6Sheets-Sheet 6 IN VENTORZ HELMVT HEeHT particularly 'toja toggle l eve'ran 'resting'of a movable rjrieriiherfaf'c y 7 her through ato'g'glelevierarran'gemem while the drive to move.

position temporarily ir'nm attached to the p'lng'er movable .die in(secreting United S rs? t siriQflf 1,738,748 TOGGLE LEvEizioiiriihTNGFOR A PRESS Hermit: He'cht, Giipl'iiflgeh (Wiimeiiib Germany, assignorto .FirmaMay-Prsseiibau G. in. b. H Schwabis'ch Gmund, GermanyA'ppiicaiio'ir names, iifsz, "6815 "12 Claims. c1. 113--3s The presentihye'fifdn relates to presses, and more n'ierit permitting are'd. byfidrive memrn'ember continues it'sfin H In the knownfopcratuigfarrange'ents for stamping presses it has, not'been possible to bnhg amovas ememibje'r operated by 'a toggle e'ver'sy 1,0313: petefs tandstill whilethe driving means onnect ed thereto continue For certain pressoperations lhoweyer, it 'is highly desirable to hold a movableniiiihrinoperative y le. In a stir ping press, for instance. the hdldihgfmmberjwhich clamps down a blank should be at a completestartdstillbefore, the die seat "the 'fstiarnping tep proper. For mold ng fpressea' s I ll, fart sting or a ly'a va'ntageous. ention 'to provide a pressinde- I It is. the objec of the pres 1 means for arresting a movableineinb pendently of the movementof a drive It 'is another "object of"the 'p in ast'amping pr'essa resilient connec member and the :to'g'glelever sy p m'ember, permitting furthe move'tiientof the dr'igve memherafter the holding member is arrested in operative position. y I y it isa further object of the vide in a press a resilie" member and aholdingto the machine in the iev'ent t at V V able member is blocked b'yexcessively,

it is a still further objejctftif, th provide in a press a eo inect nber and a holding member, drive member to the holding these membersmove, butresiliently yields movement of the holding me e blocked, thedriving member to continue mov" iii r it i fi tbv' rriding the resilientactidn of the connect 'g' in ns without any further resistance bytheconnecting J It is also an object er the present inyen'tion to provide astamping press in which a anatngrnemee and a plungermember are drivenfrom the 'same drive means and are connected to each otherbyresilie'ntly yielding connecting meanspermitting the plunger tocontinue its working stroke aftertheholdin'g member has been arrestedinoperative position. v

With these objects in view the present inventionmainly consists in amovable holding member rc ciprocably mounted in the frame of. a stampingpress a-leversystem including toggle levers connectingthe movableholding member with a drive triember and resiliently yielding connectingmeans at aged between the tog' g'le lever system and the drive'nierfihe'r. A

The resiliently yielding conriectin'g means maybe a piston slidablymounted in 'a'c'ylinder,u ed direction transversal to themoveriieiit erLe drive :niefnber by the for or a spring or by anfifiriifiye-iis'sfifi'id liifil'id in 2,738,748 M, seta, Meet? .5?

the cylinder. In the event that the drive of the press is hydraulicallyoperated, the operating liquid in the cylinder is the same as used forthe drivemember.

Preferably the axis of the cylinder of the connecting means is arrangednormal to the direction of 'movement of the drive member whereby a rigidconnection is formed in a direction of movement of the .drive member,and the resiliently yielding connection is formed for movement of thelever system normal to the direction of movement of the drive member. Iy A press according to the present invention may be driven by means of acrank shaft or by means of hydraulically operated cylinder and pistonmeans. In either case the drive member preferably performs a straightmovement in the same direction as, or in opposite direction to themovement of a movable member connected to the drive member by leversystems.

Several lever systems and resilient connecting means are provided forlarge presses exerting high pressure, and such lever systems arepreferably arranged symmetrically to .the drive member.

in a stamping press a movable member may be particularly advantageouslyemployed as a holding member for blanks, .While the plunger member mayconstitute the drive member. The driving means which may be a crankshaft rotated by a-motor, and the plunger may be arranged on the sameside or on opposite sides of the plane constituted by the surface of thepress table.

The novel features which are considered as characteristic for theinvention are set 'forth inwparticuiar in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof; willbe best understood from the following descriptionof specific embodimentswhen read in connection with the acco'mpanying drawings, in which:

Fig. l is a sectional view of a stamping press provided withahydranlically operated drive member on the line 1-.-1 of Fig. 3; y

Fig. .2 is a sectional view on line 2- -2 in Fig. 3, the toggle leversystem illustrated in. Fig. 1 being omitted;

. 'Fig'. 3 is a erossseetional view on line 3 -3 orrtg. 2;

Fig. 4 is a sectional view on line 6+4 of Fig. 3; Fig. 5 is an enlargedpartly sectional view of an operatingarrangement as shown in Fig. 1;

Fig. 6 is a view of the operating arrangement shown in Fig. 5 in anotherposition; .7

. Fig. 7 is a sectional view of'a detail on line 7-7 of Fig. 5;

Fig. 8 is a sectional view of a. stamping press driven by a rotatingcrank shaft on line 8--8 .in Fig. 10;.

Fig. 9 is a sectional view of an enlarged detail taken on line 9-9 inFig. 10; V

Fig. 10 is a cross-sectional view takenori line Iii-10 inFig.8; Y

Fig. 11 is a partly sectional view of an enlarged detail or Fig; 8;

Fig. 12 is a View similar to Fig. 11 showing a different position of theoperating arrangement; and I Fig. 13 is a sectional view of an enlargeddetail on line l3-i3 of Fig. ll.

Referi ing now to the drawings. Figs l to 4 show a hydraiilically drivenstampingpress aecdrding to" the present invention. A holding member 3 isguided in the sna snng frame n depress guiding means 2 as rod 8,carrying the piston 7, passes through openings at the ends of thecylinder 6 and is secured on one end thereof to the upper part of thesupporting frame of the machine, and on the other end to a transverselyextending bar 131 which is a part of the press body. The guiding rod 8is secured on both ends thereof to the supporting frame by means of nuts9.

The drive member, or drive cylinder 6 is provided with transversal ribs601, 602 and 603, clearly shown in Fig. 4, which are connected bylongitudinally extending ribs 604. The transversal ribs 601, 602 and 603engaging guiding members 10 which are secured to the supporting frame ofthe machine can be best seen from Figs. 3 and 4. The transversal rib 601is provided with forked projecting portions 605 extending substantiallynormal to the direction of movement of the drive cylinder in atransversal plane. The transversal rib 601 is provided with bores 606 inthe forked portions thereof which constitute cylinders in which pistonsare reciprocably movably mounted. The axes of these cylinders 606 areparallel to each other and extend in a transversal plane normal to themain axis of the machine and to the direction of movement of the drivemember. The cylinders 606 are arranged in two pairs having aligned axes,the axis of each aligned pair being parallel to the axis of the otheraligned pair and extending normal to a plane of symmetry passing throughthe drive member from the front to the rear of the machine.

Each of the four pistons 20 is connected to the holding member 3 by alever system, the four lever systems being symmetrically arranged, andexactly alike.

Each of these four lever systems comprises a lever 18, pivoted to one ofthe pistons 20 and actuating a set of toggle levers 11 and 14. The longtoggle lever 11 is pivotally connected to a member 16 which is slidablymounted in the holding member 3, and adjustable by nut and bolt means ina direction parallel to the main axis of the machine.

Two short toggle levers 14 are pivotally mounted on each of the shafts12 which are mounted on the supporting frame of the machine. Two suchshafts 12 are provided as can be clearly seen from Fig. 3. The firstlong toggle lever 11 is pivotally connected to one end of the secondshort toggle lever 14 by a pin 13 while the other end of the lever 14 ispivoted to lever 18 by a pin 19. Consequently all pivoting axes of thelever system are parallel and extend normal to the direction of movementof the drive member 6 and of the holding member 3.

The construction of the forked portions 605 and the pistons 20 can bebest seen from Figs. 5 and 7 when ex- 1 amined in connection with Fig.3. The forked portions 605 are provided with a plate 28 secured theretoby bolt and nuts and serving as a stop means for the piston 20. A port32 is provided near the other end of the cylinder 606 through which anoperating liquid may be supplied or discharged. The piston 20 is slottedas shown in Fig. 7 whereby forked portions 201 are formed for mount ingthe pivoting pin 22 of the lever 18.

The end of the short lever 14 which is pivotally connected to the lever18 is provided with a projection 25 clearly shown in Figs. 1, 5 and 6which abuts against an abutment 26 on the supporting frame of the presswhen the toggle lever 11 and 14 are in almost aligned position.

Referring again to Fig. 2, the drive cylinder 6 is pivotally connectedat 61 to levers 63 which engage two-armed toggle levers 53 which arepivoted on the shafts 12. Toggle lever 58 is pivoted by pin 59 to atoggle lever 55. Lever 63 is pivotally mounted between forked portions607 of the ribs 601 and 602 on pin 61.

As can be seen from Fig. 2, the end of the toggle lever 55 is pivoted toa member 56 which is mounted in the plunger member 53 slidably in thedirection of movement thereof and may be adjusted by worm wheel 57 and aworm (not shown).

The toggle lever systems connecting the drive member with the holdingmember 3 are arranged symmetrically in front of and behind the togglelever systems connecting the drive member with the plunger member 53,all toggle lever systems being arranged in parallel planes as can beseen from Fig. 3. The shafts 12 provide pivoting points for all threetoggle lever systems.

The arrangement operates as follows:

When the drive cylinder 6 moves upwardly the lever 18 urges the togglelevers 11 and 14 from the angular position shown in Fig. 5 to an almostaligned position shown in Fig. 6 so that the holding member 3 is moveddownwardly. Simultaneously the lever system 63, 58 and move the plungermember 53 in the same direction.

In the position shown in Fig. 5, lever 18 is in the position AA, and theholding member 3 is in inoperative lifted position. In this positionpiston 20 is urged to the left by the operating liquid contained in thecylinder 606 to engage the stop means 28. Since the drive member 6 movesnormal to the axis of the cylinder 606, the connection between piston20, and ribs 601 and the forked portion 605 thereof,'respectively, isrigid.

In the beginning of the movement of the drive member the movement of theholding member is comparatively fast in respect to the movement of theplunger member which is caused by the particular arrangement of therespective operating lever systems. After the drive member 6 has movedfor a predetermined distance turning the short toggle lever 14 about theshaft 12, the toggle levers 14 and 11 are in an almost aligned positionas shown in Fig. 6, corresponding to an operating clamping position ofthe holding member. When the toggle levers reach this position, theprojection 25 of the toggle lever 12 abuts against the stationaryabutment means 26. The lever 18 is now in the position B--B, and thetoggle levers 14 and 11 and the holding member 3 are blocked. In thisposition the blank is clamped down by the holding member.

The drive. member continues its movement and the plunger member isactuated by toggle levers 58 and 55 to carry out the stamping operation.While the drive member 6 continues its movement the lever 18 is pivotedabout the pin 19 and arrives at the position C-C as shown in Fig. 6 inbroken lines. The end of lever 18 which is pivoted to the piston 20,moves along a circle so that the piston 20 moves a distance a in thecylinder 606. Consequently, a free space must be provided between theend of the piston and the bottom of the cylinder, and the distance [2must be greater than the distance a. The cylinder 606 either contains acompressible fluid or communicates through the port 32 with a containercontaining a compressible fluid such as compressed air. In this event anoperating liquid is contained in the cylinder 606.

During further movement of the drive cylinder 6, the lever 18 turnsfurther about the pivot pin 19 and the piston 20 returns to its initialposition due to the action of the compressed fluid on the operatingliquid contained in the cylinder 606. Shortly before the piston 20arrives in the end position defined by the stop means 28 the lever 18 isin the position D-D and the movement of the drive member is terminated.When the drive member 6 moves downwardly the procedure is reversed, andfirst the plunger member 53 is moved upwardly while the piston 20performs its reciprocating movement, whereupon the toggle lever system1114 is actuated to lift the holding member 3.

Figs. 8 to 13 illustrate a press according to the present invention inwhich the plunger member is driven by crank means. 011 the upper part ofthe supporting frame of the press 17 a motor 71 is mounted driving ashaft 73 by a belt 72 and a pulley 74. Pinions 75 are arranged at theends of shaft 73. Two gears 76 each meshing with one of the pinions 75are fixedly connected to pinions 77 which mesh with the main gears 78arranged at the -ends of the crank shaft 89. -The"driving means 71 to 77are schematically indicated in broken linesjinFig. 8.

Crank shaft 79, rotatably mounted on the supporting frame of the press,drives a connecting rod .82 which is pivoted to the plunger 83. Fig. 8shows the crank in the upper dead center position, while for the sake ofclarity the crank'is shown in Fig. in a horizontal position. The holdingmember 85 is provided with a wide passage permitting the plunger memberand the die to pass therethrough. The plunger member 83 is guided on'guiding means 84 inside the'holding member, while the holding member 85is slidably guided onguiding means 86 on the supporting frame of themachine. The holding member 85 is actuated by the plunger member 83through four symmetrically arranged lever systems. Since the four leversystems are identical, only one will be described hereafter.

A shaft87, rotatably mounted in the supporting frame of the press, isconnected on one hand with the plunger member by means of twopivotedlevers 88 and '89, and on the other hand with the holding'member85'by means of a pair of toggle levers 90 and 91. 'On each shaft 87 twosuch lever systems are arranged. The plunger member 83 is provided onits upper part with two forked portions 92. A transversal bore 93 passesthrough the'entire width of the plunger member ending on both sidesthereof in forked end portions 92, as clearly shown in Figs. 9 and 11.Two pistons 94 are coaxially arranged in the bore 93, and outwardlyurged by a spring 95. Fig. 13 shows the construction'of the pistons 94in greater detail. Each piston 94 is provided at the outer end thereofwith a forked portion 96 abutting in the extreme outer position of thepiston 94 against stops 97 which are secured to forked portion 92 of theplunger member 83. In the interior of the bore 93 thespring 95 isarranged and urges the pistons 94 towards the stops 97. Since the bore93 constitutes a cylinder for the pistons 94, a-passage 104 clearlyshown in-Fig. 11, is provided to-permit air to enter and leave theinterior of the cylinder 93. On each piston 94 the lever'89 is pivotedon a pin 98 which is.

mounted in the forked portion 96. A pin 9 9 connects the lever 89 withthe lever 88. Lever 88 is fixedly mounted on the shaft 87. One endofjlever 88 is provided with an abutting portion 100 which abuts againstabutment means 101 on the supporting frame of the press after Theoperating arrangement according to the embodiment shown in Figs. 8 to 10operates as follows:

In Fig. 11 the plunger member 83 and the holding member 85 are assumedto be in their uppermost position. In such position the lever 89 is inthe position A- -A and the piston 94 is urged by spring 95 to itsoutermost position abutting on the stop means 97. When the plungermember 83 is moved downwardly within the holding member 85 along theguide means 84, the lever 89 turns the lever 83 which is pivoted theretoabouttheaxisof the stationary shaft 87, turning shaft; 87 forapredetermined angle. Thereby the short lever 90 which is fixedlyconnected to the shaft 87 is turned through the same angle so that thefirst toggle lever 91 and the. second toggle lever 90, 88 are pivotedfrom an angular position towards an aligned position causing downwardmovement of the holding member 85 since point 103 is farther spaced fromshaft 87 when the toggle levers aresubstantially aligned. When thetoggle levers are in almost aligned-position the abutting portion 100 ofthe lever 88 'engages the abutment means 101 on the machine frame in theposition B--B of "action of spring for a distancea, whileduring furthermovement of the plunger member the pistons 94 move again outwardly untilthey engage the respective stop means '97. In contrast to the embodimentshown in Figs. 1 to 7, the drive memberof theembodiment shown in'Figs. 8to 13, whichis constituted by the plunger member, moves in the samedirection as the holding memher.

In the embodiment illustrated in Figs, 8 to 13 onespring 95 is providedfor two oppositely arranged pistons 94. Even if the cylinders 96are;supplied"with an operative liquid under pressure and pistons 94areoperated hydraulically, a spring may be provided in each cylinder tourge the piston-outwardly inthe event that a disturbance in the supplyofoperating liquid occurs. In the embodiment shown in Figs. 1 to 6 suchspring may be provided in each cylinder. I I

It willbe understood that each-of the elements de scribed-above, or twoor more together, may also find a useful application in other types ofoperating lever arrangements diiiering from the types described above.

While the invention has been illustrated and described as embodied in anoperating toggle lever arrangement for a stamping presspermittingmovement of the plunger member while the holding member is arrested, itis not intended'to be-limited to the details shown, since variousmodifications and structural changes may be made without departing anany way from the spirit of the present invention. V I

Withoutfurther analysis, the foregoing will so fully reveal the gist ofthe-present; invention'that others can.

by. applyingcurrent knowledge readily adapt it for various applicationswithout omitting features that, from the standpoint of prior art, fairlyconstitute essential characteristics of the generic or specific aspectsof this invention, and therefore, such adaptations should and areintended to becomprehended within the meaning and range of equivalenceof the following claims. What is;claimed as new-and desired to besecured by-Letters Patent is: I

1. In an apparatus'of the type described, incombination, a supportingframe; a movable member re'ciprocably mounted in said supporting frame;aiirst toggle lever pivotally connected atone 'endthereof *to sai'dmovable member; a second toggle lever-pivotally mounted on saidsupporting frame turnable about a stationary axis, said second togglelayer being :pivotally connected at a point spaced fromsaid stationaryaxis to the other end of said first toggle lever, said first and secondtoggle levers being turnable relative to each other between a firstposition in which said one end of said first toggle lever is spaced fromsaid stationary axis of said second toggle lever a shorter distance, anda second position in which said one end of said first toggle leverisfspaced-from said stationary axis a greater distance; a ydrive memberreciprocably mounted in said; supporting frame movable in a planeextefidihgnormal to thepivoting axes of said toggle levers; a thirdlever pivotally connected at one end thereof to said second'toggle leverata pointspaced from said stationary axis and being operative to rotatesaid second toggle lever about said stationary axis; resilientlyyielding eonneeting means mounted onsaid drive member and pivotallyconnecting the same with the other end of said third lever so thatmovement of said drive member moves said first and said second togglelevers from said first position to said second position; and abutmentmeans fixedly seeured to saidsu-pporting frameand engaging andholdingone of said toggle levers when said toggle levers are in said secondposition so that further movement of said drive member requires andeffects yielding of said connecting means.

2. In an apparatus of the type described, in combination, a supportingframe; a movable member reciprocably mounted in said supporting frame; afirst toggle lever pivotally connected at one end thereof to saidmovable member; a second toggle lever pivotally mounted on saidsupporting frame turnable about a stationary axis, said second togglelever being pivotally connected at a point spaced from said stationaryaxis to the other end of said first toggle lever, said first and secondtoggle levers being turnable relative to each other between a firstposition in which said one end of said first toggle lever is spaced fromsaid stationary axis of said second toggle lever a shorter distance, anda second position in which said one end of said first toggle lever isspaced from said stationary axis a greater distance; a drive memberreciprocably mounted in said supporting frame movable in a planeextending normal to the pivoting axes of said toggle levers;

a third lever pivotally connected at one end thereof to said secondtoggle lever at-a point spaced from said stationary axis and beingoperative to rotate said second toggle lever about said stationary axis;connecting means slidably mounted on said drive member and pivotallyconnecting the same with the other end of said third lever so thatmovement of said drive member moves said first and said second togglelevers from said first position to said second position; resilient meansurging said connecting means in one direction; and abutment meansfixedly secured to said supporting frame and engaging and holding one ofsaid toggle levers when said toggle levers are in said second positionso that further movement of said drive member requires and effectsyielding of said connecting means.

3. In an apparatus of the type described, in combination, a supportingframe; a movable member reciprocably mounted in said supporting frame; afirst toggle lever pivotally connected at one end thereof tosaid movablemember; a second toggle lever pivotally mounted on said supporting frameturnable about a stationary axis, said second toggle lever beingpivotally connected at a point spaced from said stationary axis to theother end of said first toggle lever, said first and second togglelevers being turnable relative to each other between a first position inwhich said one end of said first toggle lever is spaced from saidstationary axis of said second toggle lever a shorter distance, and asecond position in which said one end of said first toggle lever isspaced from said stationary axis a greater distance; a drive memberreciprocably mounted in said supporting frame movable in a planeextending normal to the pivoting axes of said toggle levers; a thirdlever pivotally connected at one end thereof to said second toggle leverat a point spaced from said stationary axis and being operative torotate said second toggle lever about said stationary axis; connectingmeans slidably mounted on said drive member and pivotally connecting thesame with the other end of said third lever so that movement of saiddrive member moves said first and said second toggle levers from saidfirst position to said second position; spring means urging saidconnecting means in one direction; and abutment means fixedly secured tosaid supporting frame and engaging and holding one of said toggle leverswhen said toggle levers are in said second position so that furthermovement of said drive member requires and eifects yielding of saidconnecting means.

4. In an apparatus of the type described, in combination, a supportingframe; a movable member reciprocably mounted in said supporting frame; afirst toggle lever pivotally connected at one end thereof to saidmovable member; a second toggle lever pivotally mounted on saidsupporting frame turnable about a stationary axis, said second togglelever being pivotally connected at a point spaced from said stationaryaxis to the other end of said first toggle lever, said first and secondtoggle levers being turnable relative to each other between a firstposition in which said one end of said first toggle lever is spaced fromsaid stationary axis of said second toggle lever a shorter distance, anda second position in which said one end of said first toggle lever isspaced from said stationary axis a greater distance; a drive memberreciprocably mounted in said supporting frame movable in a planeextending normal to the pivoting axes of said toggle levers; a thirdlever pivotally connected at one end thereof to said second toggle leverat a point spaced from said stationary axis and being operative torotate said second toggle lever about said stationary axis; a cylinderfixedly mounted on said drive member; a piston reciprocably mounted insaid cylinder and ivotally connected with the other end of said thirdlever so that movement of said drive member moves said first and secondtoggle levers from said first position to said second position; acontainer communicating with said cylinder so that a compressed fiuidcontained in said container urges said piston in one direction; andabutment means fixedly secured to said supporting frame and engaging andholding one of said toggle levers when said toggle levers are in saidsecond position so that further movement of said drive member requiresand effects yielding of said piston.

5. In a press, in combination, a supporting frame; a movable blankholding member reciprocably mounted in said supporting frame; a firsttoggle lever pivotally connected at one end thereof to said movableblank holding member; a second toggle lever pivotally mountedintermediate its ends on said supporting frame turnable about astationary axis, one end of said second toggle lever being pivotallyconnected to the other end of said first toggle lever, said first andsecond toggle levers being turnable relative to each other between afirst position in which said one end of said first toggle lever isspaced from said stationary axis of said second toggle lever a shorterdistance, and a second position in which said one end of said firsttoggle lever is spaced from said stationary axis a greater distance; ahydraulically operated drive member reciprocably mounted in saidsupporting frame movable in a plane extending normal to the pivotingaxes of said toggle levers; a third lever pivotally connected at one endthereof to the other end of said second toggle lever and operative torotate said second toggle lever about said stationary axis; a cylinderfixedly mounted on said drive member; a piston reciprocably mounted insaid cylinder and pivotally connected with the other end of said thirdlever so that movement of said drive member moves said first and saidsecond toggle levers from said first position to said second position; acontainer communicating with said cylinder so that a compressed fluidcontained in said container urges a portion of said operating liquidcontained in said cylinder and thereby said piston in one direction; andabutment means fixedly secured to said supporting frame and blockingsaid movable member and said toggle levers when said toggle levers arein said second position so that further movement of said drive memberrequires and efiects yielding of said piston.

6. In an apparatus of the type described, in combination, a supportingframe; a movable member reciprocably mounted in said supporting frame; afirst toggle lever pivotally connected at one end thereof to saidmovable member; a second toggle lever pivotally mounted on saidsupporting frame turnable about a stationary axis, said second togglelever being pivotally connected at a point spaced from said stationaryaxis to the other end of said first toggle lever, said first and secondtoggle levers being turnable relative to each other between a firstposition in which said one end of said first toggle lever is spaced fromsaid stationary axis of said second toggle lever a shorter distance, anda second position in which said one V end of said first toggle lever isspaced from said stationary axis a greater distance; a drive memberreciprocably mounted "in said supportingframe movable in a planeextending'normal 'to the pivoting axes of said toggle levers; athirdlever'pivotally connected'at one'end thereof to said'second togglelever at a point spaced from said stationary'axis'and being operative torotate said second toggle lever'about said stationary axis; a cylindermounted on saiddrive memberand having an axis normal to saiddir'ectiomofmovement of said holding member and to said pivotingyaxes ofsaid toggle lever means; a piston reciprocably mounted insaid cylinderand pivotally connected. with'theother end'of said third lever so thatsaid drive member, when moving, pivots said first and said'second togglelevers from said'first position to'said second position while saidpiston remains immovably in saidcylinder; abutment means fixedly securedto said supporting'frame and blocking movement of said toggle levermeansand of said holding member when said toggle-lever means are in saidsecond position so that further movementof'said drive member effectsmovement of-said pistonin'said cylinder; resilient means urging saidpiston andsaid third lever toward said abutment means; and stop; meanson one end of said cylinder holding said piston in an-endpositionagainst the action of said resilient means.

7. In an apparatus of the type described, in combination; a supportingframe; a movable member reciprocably mounted-in said supporting frame; afirst toggle lever pivotally-'connectedat' one endthereof to saidmovablemember; a second toggle lever pivotally mounted on said supportingframeturnable about a stationary axis, said second toggle lever beingpivotally connected at a point spaced fromi said? stationary axis to theother end of said first toggle lever, said. first and second togglelevers being turnable relative to each other between a first position inwhich said one endof saidfirst. toggle lever. isspaced from saidstationary axisof saidsecond toggle. lever: a shorter distance, and-asecond .position in which. said one end ofsaid firsttogglelever is.spaced :from saidstationary axis a greater distance; a drive memberreciprocably mounted in said supporting frame movable in a planeextending normal to the pivoting axes of said toggle levers; a thirdlever pivotally connected at one end thereof to said second toggle leverat a point spaced from said stationary axis and being operative torotate said second toggle lever about said stationary axis; a cylindermounted on said drive member and having an axis normal to said directionof movement of said holding member and to said pivoting axes of saidtoggle levers; a piston reciprocably mounted in said cylinder andpivotally connected with the other end of said third lever so that saiddrive member, when moving pivots said first and said second togglelevers from said first position to said second position while saidpiston remains imrnovably in said cylinder; abutment means fixedlysecured to said supporting frame and engaging said toggle leversblocking further movement of the same and of said holding member whensaid toggle lever means are in said second position, said one end ofsaid third lever being located forwardly in the direction of movement inrespect to the other end thereof when said abutment means engages saidtoggle levers so that further movement of said drive member effectsreciprocation of said piston in said cylinder; resilient means urgingsaid piston and said third lever toward said abutment means; and stopmeans on one end of said cylinder holding said piston in an end positionagainst the action of said resilient means.

8. In a press, in combination, a supporting frame; a reciprocable blankholding member slidably guided in said supporting frame movable in onedirection; a first toggle lever connected at one end thereof to saidblank holding member pivotable about an axis normal to the direction ofmovement of said blank holding member; a second toggle lever mounted atone end thereof on said supporting frame pivotable about a stationaryaxis parallel to said axis, the other end of said second toggle leverbeing pivoted toathe; otherend; of said: first toggle lever forpivotalmovement-about an axis parallel tosaidnaxes,v said first and'secondtoggle: levers being turnable relative to each. other between: 1a. first position in which said, i one end of said first toggle-lever isspaced. from said stationaryaxis of saidsecondrtoggl'e; lever a shorterdistance and a secondpositionin. which said one end of said first,

toggle lever is spacedqfrom said stationary axis a greater distance; athirdlever; pivotally connected at one end thereof to said other end ofsaid second toggle lever and being operative to:rotate said secondtoggle lever about' said. stationary axis; a drive member slidablymounted in said. supporting frame reciprocably-movable in said'directionof movement of saitlholding member; a cylinder mounted onsaiddrivemember and having an axis normal to said direction'of movementof saidholding member and. to said-pivoting; axes of said toggle levers;a piston reciprocably mountedin said cylinder and pivotally connectedwith the-other end of said third lever so thatsaid drive member, whenmoving pivots said-first and said second=toggle levers from said firstposition to said second position. while said;piston remains immovably insaid cylinder;abutment,means fixedly secured to said supporting frameandsengagingsaid toggle levers blocking-further: movement of thesame andof said holding member. whensaidtoggle. lever means are insaid secondposition, saidone endv of said third lever being located forwardly inthe. direction of movement; in respect to the other endthereof'wlrensaid abutmentmeans engages said toggle levers so that'further movementofsaid drive member: effectsreciprocation of: said piston in saidcylinder; resilient meansurging. said piston and said third levertoward-saidabutment means;and stop means on oneend of: said cylinder;holding. said piston in an end position against the action of saidresilient means.

9;. In an apparatus ofthe. type, described, in combination; a.supporting'framq'a movable :member reciprocably mounted'in said;supporting frame; a first toggle lever pivotally connected at one endthereof to said movable member; a second toggle lever pivotally mountedon said supporting frame turnable about a stationary axis, said secondtoggle lever being pivotally connected at a point spaced from saidstationary axis to the other end of said first toggle lever, said firstand second toggle levers being turnable relative to each other between afirst position in which said one end of said first toggle lever isspaced from said stationary axis of said second toggle lever a shorterdistance, and a second position in which said one end of said firsttoggle lever is spaced from said stationary axis a greater distance; adrive member rcciprocably mounted in said supporting frame movable in aplane extending normal to the pivoting axes of said toggle levers; athird lever pivotally connected at one end thereof to said second togglelever at a point spaced from said stationary axis and bein operative torotate said second toggle lever about said stationary axis; resilientlyyielding connecting means mounted on said drive member and connectingthe same with the other end of said third lever so that movement of saiddrive member moves said first and second toggle levers from said firstposition to said second position; and abutment means blocking turning ofsaid toggle levers relative to each other beyond said second position sothat further movement of said drive member requires and effects yieldingof said connecting means.

10. An operating arrangement as claimed in claim 1 and including anotherfirst toggle lever; another second toggle lever; another third lever;another connecting means; and another abutment means, all cooperating inthe same manner as the corresponding elements claimed in claim 1 andarranged symmetrically to the same with respect to the plane of symmetryof said movable member extending in the direction of movement thereof.

11. An operating arrangement as claimed in claim 7 and including anotherfirst toggle lever; another second toggle lever; another third lever;another piston reciprocably mounted in said cylinder; and another stopmeans on the other end of said cylinder, all cooperating in the samemanner as the corresponding elements claimed in claim 7 and arrangedsymmetrically to the same with respect to a plane of symmetry of saidholding member extending in the direction of movement thereof, saidresilient means being arranged in said cylinder between said piston andsaid other piston urging said two pistons apart.

12. In a press, in combination, a supporting frame; a reciprocableholding member slidably guided in said supporting frame movable in onedirection and in opera tive position adapted to clamp down a workpiece;two parallel shafts mounted in said supporting frame and extendingnormal to the direction of movement of said holding member on eitherside of the same; four first toggle levers, each connected at one endthereof to said holding member pivotally about an axis extendingparallel to said shafts; two pairs of second toggle levers, each pair ofsecond toggle levers pivotally mounted intermediate the ends thereof onone of said parallel shafts, one end of each of said second togglelevers and the other end of each of said first toggle levers beingconnected pivotally about an axis extending parallel to said axis, eachset of associated first and second toggle levers being turnable relativeto each other between a first position in which said one end of saidfirst toggle lever is spaced from said stationary axis of said secondtoggle lever a shorter distance, and a second position in which said oneend of said first toggle lever is spaced from said stationary axis agreater distance; a drive member slidably mounted in said supportingframe reciprocable in said direction of movement of said blank holdingmemher, two of said first and second toggle levers being located on oneside of said drive member, and the other two of said first and secondtoggle levers being located on the other side of the same; four thirdlevers, each third lever pivotally connected at one end thereof to theother end of one of said second levers and being operative to rotate thesame about the associated shaft; four cylinders mounted on said drivemember, two of said cylinders being located on each side of said drivemember, each of said cylinders having an axis normal to said directionof movement of said holding member and to said pivoting axes of saidlevers; four pistons, each piston reciprocably mounted in one of saidcylinders and pivotally connected with the other end of one of saidthird levers so that said drive member, when moving, pivots said firstand second toggle levers from said first position to said secondposition while said pistons remain immovably in said cylinders; fourabutment means, each abutment means fixedly secured to said supportingframe and engaging one of said sets of associated first and secondtoggle levers blocking further movement of the same and of said holdingmember when said toggle levers are in said second position, said one endof each of said third levers being located forwardly in the direction ofmovement in respect to the other end thereof when said abutment meansengage said toggle levers so that further movement of said drive memberefiects movement of said pistons in said cylinders; resilient meanslocated in each of said cylinders and urging the respective piston andthe third lever associated therewith towards the associated abutmentmeans; and stop means on one end of each of said cylinders holding thepiston associated with the same in an end position against the action ofthe resilient means associated therewith.

References Cited in the file of this patent UNITED STATES PATENTS1,796,786 Hatch Mar. 17, 1931 1,993,839 Hatch et al. Mar. 12, 19352,105,053 Patrick Jan. 11, 1938 2,224,968 Klocke Dec. 17, 1940

